\(\frac{M+1}{M+5}\frac{M+11}{M+15}SOSANH\)
Ai nhanh tay minh tick cho nhe !
\(\frac{m+1}{m+5}\)\(\frac{m+1}{m+5}\)so sánh m > 0
ai nhanh tay minh tick cho !
toan lop 5
\(\frac{achia5+1}{15}=5\)
ai nhanh tay minh tich cho nhe !
\(\frac{a:5+1}{15}=5\)
(a : 5 + 1) : 15 = 5
a : 5 + 1 = 5 x 15
a : 5 + 1 = 75
a : 5 = 75 - 1
a : 5 = 74
a = 74 x 5
a = 370
\(a=370\)Vì
\(\frac{370:5+1}{15}=\frac{75}{15}=5\)
Cho M=\(\frac{1}{10}\)+\(\frac{1}{11}\)+\(\frac{1}{12}\)+\(\frac{1}{13}\)+\(\frac{1}{14}\)+\(\frac{1}{15}\)+\(\frac{1}{16}\)+\(\frac{1}{17}\)+\(\frac{1}{18}\)+\(\frac{1}{19}\)+\(\frac{1}{20}\)
Chứng minh: \(\frac{11}{15}\)<M<\(\frac{5}{6}\)
Ai nhanh mình tick
\(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+;;;;+\frac{1}{110}\)
AI NHANH TAY TICK 5 LAI NHE !
\(A=\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+...+\frac{1}{110}\)
\(A=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{10.11}\)
\(A=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{10}-\frac{1}{11}\)
\(A=1-\frac{1}{11}\)
\(A=\frac{10}{11}\)
\(\frac{a;a+5}{25}=\frac{1}{5}\)
ai nhanh tay minh tich 5 lai cho nhe !
Tính nhanh
a)\(7.\left(\frac{3}{8}+\frac{11}{17}\right)-11.\frac{7}{17}+7.\frac{5}{8}\)
ai làm nhanh+đúng mik tick cho
7.(\(\frac{3}{8}+\frac{11}{7}\)) - 11.\(\frac{7}{17}\) + 7.\(\frac{5}{8}\)
= 7(\(\frac{3}{8}\) +\(\frac{11}{7}\) -\(\frac{11}{7}+\frac{5}{8}\))
=7(\(\frac{3}{8}+\frac{5}{8}\))
= 7.1
=7
cho tam giac abc co day BC =36 cm tren ac lay diem m sao cho cm =1/3 ac. tren ab lay diem n sao cho 1/3 ab.noi n voi m. tinh mn theo day bc
ai nhanh tay minh se tick cho nhe! cac ban nhhanh gium minh dang can rat gap
\(\frac{1}{5}< y< 1\)
ai nhanh tay tick 5 lai nhe !
Y có thể là :
\(\frac{2}{5},\frac{3}{5},\frac{4}{5}\)vì các phân số này đều nhỏ hơn 1.
K nhá
cho M = \(\frac{3}{4}+\frac{8}{9}+\frac{15}{16}+\frac{24}{25}+...+\frac{399}{400}.\)
a> chứng tỏ M > 8
b> chứng tỏ M < 9
ai nhanh mình tick
\(a)\)\(M=\frac{3}{4}+\frac{8}{9}+\frac{15}{16}+...+\frac{399}{400}\)
\(M=\frac{4-1}{4}+\frac{9-1}{9}+\frac{16-1}{16}+...+\frac{400-1}{400}\)
\(M=1-\frac{1}{4}+1-\frac{1}{9}+1-\frac{1}{16}+...+1-\frac{1}{400}\)
\(M=\left(1+1+1+...+1\right)-\left(\frac{1}{4}+\frac{1}{9}+\frac{1}{16}+...+\frac{1}{400}\right)\)
\(M=\left(1+1+1+...+1\right)-\left(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{20^2}\right)\)
Do từ 2 đến 20 có \(20-2+1=19\) nên :
\(M=19-\left(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{20^2}\right)\)
Đặt \(A=\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{20^2}\)
\(A>\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{20.21}\)
\(A>\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{20}-\frac{1}{21}\)
\(A>\frac{1}{2}-\frac{1}{21}\)
\(\Rightarrow\)\(M=19-A>19-\frac{1}{2}+\frac{1}{21}=18,5+\frac{1}{21}>8\)
\(\Rightarrow\)\(M>8\) ( đpcm )
Còn câu b) bn xem lại đề đi, nếu đề đúng thì mk sai :v
Chúc bạn học tốt ~
\(M=\frac{3}{4}+\frac{8}{9}+\frac{15}{16}+\frac{24}{25}...+\frac{399}{400}\)
\(=\left(1-\frac{1}{4}\right)+\left(1-\frac{1}{9}\right)+\left(1-\frac{1}{16}\right)+\left(1-\frac{1}{25}\right)+...+\left(1-\frac{1}{400}\right)\)
\(=\left(1+1+1+....+1\right)-\left(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+\frac{1}{20^2}\right)\)
\(=19-\left(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{20^2}\right)\)
Đặt \(N=\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+....+\frac{1}{20^2}\)
\(< P=\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+....+\frac{1}{20\cdot21}\)
\(=\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{4}+\frac{1}{5}-\frac{1}{6}+...+\frac{1}{20}-\frac{1}{21}\)
\(=\frac{1}{2}-\frac{1}{21}\)
\(\Rightarrow M+N>19-\frac{1}{2}+\frac{1}{21}=\frac{37}{2}+\frac{1}{21}>8\)
b sai đề.chừng nào chữa đề thì làm